The present invention relates generally to theatrical rigging systems, and more particularly to rigging systems that utilize counterweights to raise and lower the load.
Most existing rigging systems use manually operated rigging sets (or “sets”), which are counterbalanced with weights for ease of operation. When loads (scenery, curtains, lighting equipment, etc.) are changed, the counterbalancing weights must be adjusted to properly balance the load. This normally happens when the load is at floor level and counterbalancing weights are substantially above the floor, making access difficult.
In their most basic form, conventional rigging sets, such as the one illustrated in FIG. 1 and designated generally by reference numeral 10, comprise a locking rail 12 fixed to the floor, a tensioning floor block 14 around which a control line 16 passes, a counterweight arbor 18 the opposing sides to which opposite ends of the control line 16 attach, a head block 20 around which control line 16 passes and which gather lift lines 22 that otherwise extend between arbor 18 and a batten 26 to which the load is attached. To raise and lower batten 26, counterweights must be removed from or added to arbor 18. This requires the rigging operator to manually remove or place weights onto arbor 18 generally at a relatively significant height.
In addition, it is necessary to ensure that a rope lock 28 is engaged to prevent sudden movement of the control line and counterweights when the operator balances the load with the counterweights. If the rope lock 28 fails or is not engaged in the first place, the arbor will rise or fall at significant speed, very likely causing serious injury and perhaps killing the operator. In addition, the amount of weight to balance the load must be carefully selected to ensure that the load is within the strength capability of the operator. Failure to do so can cause injury or death to the operator and the people on the stage below the load.
Many of these rigging systems are used in middle school and high school theatres. There are concerns about the ability of the operators (frequently students) to properly balance the loads, and the requirement for the balancing work to be done at substantial heights.
Because of the compact nature of typical counterweight rigging installations, a counterweight rigging system using a motorized winch requires a motorized winch sized to fit in a space approximately equal to the center-center spacing between adjacent rigging systems. Motorized winches of that size and also having sufficient power to operate a counterweight-assisted rigging system are expensive or have other characteristics that make them unsuitable for theatrical installations. Economical motorized winches having sufficient power to operate a typical counterweight-assisted system generally are larger than the spacing between adjacent counterweight rigging system.